<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Cursor position and drag image</title>
<script type="application/ecmascript">
function start(event)
  {event.dataTransfer.effectAllowed = 'copy';
  event.dataTransfer.setDragImage(document.querySelector('canvas'), 50, 50);}
</script>
</head>
<body>
<p><a href="data:text/plain,1" ondragstart="start(event)">Drag me</a></p>
<p>Try to drag link above. Feedback overlay should be based on canvas below and mouse pointer should be anchored in its center.</p>
<p>
  <canvas width="100" height="100">Canvas</canvas>
</p>
<script type="application/ecmascript">
var canvas = document.querySelector('canvas'),
c = canvas.getContext('2d');
for(var x = 0; x != 50; x++)
  {c.fillStyle = (x%2 == 0)?'navy':'white';
  c.beginPath();
  c.moveTo(x,x);
  c.lineTo(100-x,x);
  c.lineTo(100-x,100-x);
  c.lineTo(x,100-x);
  c.closePath();
  c.fill();}
</script>
</body>
</html>
